How to Use The Snap-On MODIS With the ever increasing electronic content in today's vehicles, the scan tool has become the tool of choice to look into the ECM or module func-tions. The scanner is the only window into what the different modules are doing. One thing's to use an oscilloscope or GMM, but to know what the computer is actually interpreting, your only choice is this piece of equip-ment. This book is different than other book on the MODIS. This book actually teaches you how to use the equipment and interpret the PID datastream. This book also borrows from some of our other publications, but geared towards the Modis. We also expose the use of other diagnostic equipment and how to use them together. In today's automotive repair shop the technician has to be able to use the equipment and draw relational char-acteristics between the signal. It is from these relations that the tech ar-rives to the true repair. It's not just using the Modis. It's using the Modis and see if the scope and multi-meter readings also support the repair conclusion. Snap-On has over the years developed into a leader in diagnostic equip-ment. With that in mind, lets learn to use the MODIS to its fullest and be-come a profitable, top technician. Remember, learning to use your equip-ment will also teach you a great deal of diagnostics. Table of Contents Basic Features Modular Diagnostic System BUTTON ARRANGEMENT DESCRIPTION UPDATING THE MODIS SCANNER GRAPHING THE PIDs SAVING YOUR SCREEN SNAP-SHOTS AND BULDING YOUR OWN LIBRARY A WORD ABOUT THE BATTERY CARE and MAINTENANCE GENERAL SCANNER FUNCTION & PID ANALYSIS THEORY OF OPERATION BEHIND THE DIFFERENT PARAMETERS (PIDs) OBD I and OBD II, and general PID analysis FUEL DELIVERY FAULT DETECTION TEST 1 - Misfire detection strategy (EGR, ignition and mechanical mis-fires) TEST 2 - A/F RATIO FAULTS TEST 3 - CLOGGED EXHAUST The MODIS Troubleshooter GRAPHING THE PIDs THE SNAP-SHOT FEATURE OBD-2 Operability Using the MODIS in conjunction with other types of equipment (Test-Light, Amp-Probes, GMM, DVOM, Oscilloscope)"